Telecommunication services have expanded remarkably in recent years. Subscribers have gained increasing flexibility in the selection and implementation of the various features that are available. A popular option provides the subscriber with the ability to determine in advance alternate destinations for an incoming call that is intended by a dialer for connection to the subscriber's telephone line. Several prior art call forwarding arrangements have been developed.
Boratgis et al., U.S. Pat. No. 4,670,628, discloses an automatic call forwarding device which is connected to a forwarding phone having a three-way conference service by a single phone line to central exchange telephone equipment. The device operates to cause a calling phone to be put on hold while a message transmitting and storage device transmits telephone dialing pulses corresponding to the number of a third phone to which the call is to be forwarded. The device is adapted to be reprogrammed by encoder signals provided by tone pulses of a standard touch tone telephone.
Rais et al., U.S. Pat. No. 4,475,009, discloses a system for remotely controlling call forwarding for a given telephone line. The call forwarding is initiated by sequentially applying a call forwarding initiate code and thereafter a desired call forwarding telephone number stored by input means connected to a given telephone line. The given telephone line is seized when an incoming call to the line is placed, and the call is forwarded to the stored telephone number.
Morganstein, U.S. Pa. No. 4,809,321, 5,027,384 and 5,029,196, describe user programmable telecommunications systems, which allow a called party to preprogram alternate destinations for incoming calls in response to a busy or no-answer status of the called party. A calling party can be apprised by a verbal prompt of an alternate destination at which the called party then may be available. The system provides an initial greeting to all incoming calls which may identify the called party and may issue a statement as to the nonaccessible condition of the intended telephone set. The incoming calls can be routed to a voice store and forward facility so that a verbal message can be deposited by the calling party.
Suzuki et al., U.S. Pat. No. 5,018,194, discloses a switching system for effecting call forwarding between subscribers. Discrimination information is added to the data for respective subscriber terminals. Each subscriber terminal may be registered in a storage unit as a single alternative destination for forwarding a call by another subscriber terminal. The inhibition of a subscriber terminal from being registered as more than one alternative destination avoids an endless loop at the stage of the call forward registration.
Davidson et al., U.S. Pat. No. 5,023,868, discloses an automated call handling apparatus for use with one or more ISDN switches connected to telephone stations. A computer connected to the switching system responds to an associated message indicating an incoming call to one of the stations by selecting an alternate destination station and transmitting digital messages to cause the switching system to forward the incoming call to the selected alternate destination. Incoming calls are forwarded in accordance with predefined criteria. The computer can answer an incoming call with a recorded message which may prompt a caller to leave a message.
Hanle et al. U.S. Pat. No. 5,012,511, describes conventional call forwarding schemes, including the enablement by a subscriber of the call forwarding feature by remote access. In the Hanle et al. arrangement, remote programming of a switch for call forwarding may be made by a subscriber on a high speed basis.
Conventional call forwarding service, as exemplified by the above described patents, generally permits the subscriber to effect reprogramming of the switch, or a computer associated with the switch, to control processing of calls directed to an individual subscriber line. The service is a switch feature wherein an incoming call will terminate on the line side of the switch and be forwarded to a programmed alternate destination. While the programming need not necessarily be undertaken from the telephone set associated with the subscriber line, each programming operation is performed for a single line or at most for a few lines or numbers.
The set up of the call forwarding service for a single line or number at one time is burdensome for subscribers having a large number of subscriber lines or numbers or, for example, subscribers having a PBX serving many extension sets. In the event of a Central Office failure, PBX failure, cable cut, fire, flood or other disaster, the subscriber would have to undertake a call forwarding set up procedure for each of the multitude of lines.
The ability to designate substitute call destinations for a large plurality of lines is desirable in many situations other than disaster conditions. A large business subscriber may require incoming calls to some or all lines of one department to be redirected to lines of one or more other departments. Such a subscriber may want to break the large organization into smaller sectors. A sector might be a floor, a department, a building or some breakdown less than the whole organization.
The organization may be dispersed over a wide geographical area. If sectors operate during different business hour schedules, it would be beneficial to redirect all incoming calls for sectors that are closed at a given time to other sectors that are open for business. A smaller business, on the other hand, may need to redirect calls to all of its lines to a single substitute location.
Conventional call forwarding severely limits the subscriber's ability to redirect incoming calls on such organizational bases. The need exists for redirecting with ease a large quantity of telephone numbers in groupings selected by the subscriber. For example, if calls are received in greater quantity than the incoming lines can handle at peak business hours, it would be desirable to have overflow calls redirected to a second location during such period. Similarly, if a redirected location is not capable of handling a full load of redirected calls, it would be desirable to have the ability to redirect such calls either on an apportioned basis to more than a single location, or on a selectable basis to multiple locations. Thus the party making an incoming call could be greeted with a recording such as: "We are experiencing a communication failure. If you press `1,` we will redirect you to our New Jersey office; press `2,` and we will redirect you to voice mail; press `3,` and we will redirect you to the Company operator." Another desirable feature would be to redirect calls on a selective basis depending on the identity of the calling party or number. Conventional call forwarding systems, however, fail to meet any of these needs.
The above discussed needs of a subscriber to service incoming calls to telephone lines which are not able to receive those calls exist even if the subscriber does not have operable secondary locations. In those instances, it would be desirable to be able to advise the caller that the dialed destination is not available for telephone conversation and to provide the caller an opportunity to leave an appropriate message. Conventional call forwarding devices do not permit redirection of a large number of telephone line destinations to a voice messaging service with, for example, messages for particular subscriber departments individually grouped.
Additional disadvantages of conventional call forwarding stem from the fact that the programming of the alternate location resides in the central office switch or a processor associated closely therewith. Voice or data calls are transmitted to and terminated at the switch and then forwarded. Lines that need not be used in the final voice or transmission connection are unnecessarily tied up. The time necessary to make the final connection over the diverted route is longer than would occur if the ultimate voice or data connection were made directly.